How and When the Earth and Moon Formed - SciTechDaily

It grew larger thanks to countless collisions between dust particles, asteroids, and other growing planets, including one last giant impact that threw enough rock, gas, and dust into space to form the moon.

Although the rocks that record the earliest parts of Earth’s history have been destroyed or deformed by more than four billion years of geology, scientists can use modern rocks, moon samples, and meteorites to figure out when and how the Earth and moon formed, and what they might once have looked like.

This vapor formed a disc around the Earth that eventually cooled and clumped together to become the moon!

Understanding how the Earth and moon formed is important for piecing together the history of the solar system and answering questions like how long planets take to form, what planets are made of, and what makes a planet suitable for life.

Radioactive elements like uranium and hafnium are trapped inside the minerals that make up these objects when they form, which allows planetary scientists to tell how old they are?

Several different formation theories for the moon have been proposed by scientists, The story that is best supported by all the available data, however, is that the moon formed during a giant impact between the proto-Earth, and another protoplanet roughly the size of Mars, sometimes known as “Theia.”.

In this theory, the moon formed from the impact debris—a mixture of molten rock and hot gas—flung out into space by the impact, potentially forming a disk of material known as a “lunar synestia.”.

Samples of rock from the moon, brought to Earth by lunar meteorites and the Apollo moon landings, can be used to understand the history of the Moon and its relationship to the Earth through the chemistry of their minerals.

Andy Davis in the Geophysical Sciences Department at the University of Chicago make precise measurements of lunar samples to determine exactly what they’re made of, and identify the chemical fingerprints of different geological processes like the melting and mixing of rocks and the evaporation of gasses.

So, by measuring the oxygen isotopes of a given planet, planetary scientists can calculate the different types of asteroid that collided to form the planet.

Other scientists propose that after the impact all of the oxygen was able to move around in the hot vapor surrounding the Earth and moon, mixing up all the different oxygen isotopes and erasing any original differences between the Earth and Theia?

Another is that when the moon formed it started off very hot with a deep magma ocean — like the Earth — and the low gravity and lack of atmosphere on the moon allowed volatile elements that wouldn’t escape from a larger object to evaporate into space.

Scientists believe the moon formed during a giant impact about 60-175 million years after the solar system was born.

This allows materials with different densities to separate, with metals like iron and nickel sinking to the inside to form a core and lighter rocks “floating” on top.

By the time of the moon-forming impact, the Earth was already separated into these rock and metal layers.

However, the intense force and heat of the impact re-melted the proto-Earth, re-mixing the separated rock and metal.

After this mixing, the Earth was still hot enough for separation to occur again and form new rock and metal layers — this is the key to dating when the moon formed.

Elements like hafnium prefer to be mixed in with rock than with metal.

The first time the Earth cooled and separated into rock and metal layers was early in the solar system’s history, so lots of hafnium was present in the Earth’s rocky layer because it hadn’t had time to decay to tungsten yet!

Elements like tungsten prefer to be mixed in with metal, so when the impact remixed the Earth, the newly formed tungsten sank into the metal core.

The concentration of tungsten in Earth’s rocks depends on when the most recent separation into rock and metal layers occurred.

The concentration of tungsten in Earth’s rocks is too low to be explained by the metal and rock separating early on, which means something must have re-mixed the Earth’s layers.

After the moon-forming impact, Earth was a very different planet from the world we see today.

Like the Earth, the moon started off with a thick layer of molten rock on its surface.

(Planetary scientists can use the fact that this feldspar crust formed on the moon but not on the Earth to try and work out differences in the early chemistry and cooling conditions between the two objects to learn more about the moon’s formation.).

This melting produced basalt, a kind of dark-colored rock commonly found at volcanoes on Earth today in places like Hawaii and Iceland.

Planetary scientists have calculated the distance between the Earth and the Moon backwards in time and found that the moon used to be seventeen times closer (14,000 miles vs. 250,000 miles) when it formed.

This changing distance between the Earth and the moon is an important clue about the details of the moon-forming impact because changing the size, speed and angles of approach of impactors in moon formation simulations changes the orbit of the final Earth-moon system.

Planetary scientists need to find an impact simulation that can not only match the moon’s chemistry, but also how far it was from the Earth and how fast it was initially spinning!

Lab experiments help scientists better understand what happens to different rock types and elements under the extreme conditions of large impact events.

Nicolas Dauphas’ research group at UChicago evaporates metals under a vacuum to simulate the conditions present in the cloud of impact debris to try and explain why lunar rocks have so much less of elements like sodium, zinc, and potassium compared to the Earth.

In the future, new samples from the moon could give planetary scientists a wider range of different lunar rock types to work with.

The more measurements scientists have, the more ways they can test different theories about how our moon formed, its relationship to the Earth, and perhaps even how moons might be born around other planets far beyond our solar system.

Direct Apollo Moon rock dating yielded a hafnium/uranium date of 60 million years after system formation in 2017 [“How Old Is the Moon

How and when did the Earth and Moon form, an article that appears to be a collection of data from many sources

While I’m here, the Earth, Mars, Moon and the Asteroid belt, were all formed in the same collision event, between dinosaur Earth and an ice planet